Steel A3 vs A8
Steel · grade comparison
Steel A3 and A8 are both steel grades, both tool steel. A8 is the stronger of the two: yield strength 500 MPa (72.5 ksi) against 430 MPa (62.4 ksi) for A3, about 16% more. In exchange, A3 is the more ductile: elongation 20% versus 18% for A8.
A3Choose it when the part is bent, formed or impact-loaded.
A8Choose it when strength drives the design.
A3 vs A8: propertiesHow to read these bars
- One bar per material. A full bar is the highest value among all steel grades in the FabDigit library; each bar is drawn as a share of that.
- The better value (by the usual engineering direction) is in bold. Rows with no direction — density, thermal conductivity — have no bold.
- Values are typical room-temperature figures for the condition named on each card.
- Confirm against the certified mill or resin datasheet before design release.
How to read these bars
- One bar per material. A full bar is the highest value among all steel grades in the FabDigit library; each bar is drawn as a share of that.
- The better value (by the usual engineering direction) is in bold. Rows with no direction — density, thermal conductivity — have no bold.
- Values are typical room-temperature figures for the condition named on each card.
- Confirm against the certified mill or resin datasheet before design release.
Mechanical
Strength, stiffness, ductility and hardness at room temperature.
Elastic (Young's) Modulus
Shear Modulus
Tensile Strength (Ultimate)
Yield Strength (0.2% offset)
Elongation at Break
Reduction in Area
Shear Strength
Charpy V-Notch Impact (RT)
Hardness, Brinell
Hardness, Rockwell B
Hardness, Rockwell C
Hardness, Vickers
Same in both: Bulk Modulus 160 GPa23.2 Msi · Poisson's Ratio 0.29 · Compressive Strength 900 MPa131 ksi
Physical
Density and transition temperatures.
Density
Same in both: Melting Point (Solidus) 1,420°C2,588 °F · Liquidus Temperature 1,470°C2,678 °F
Thermal
How each material carries heat and how hot it can run.
Thermal Conductivity
Thermal Expansion (CTE, 20–100 °C)
Same in both: Specific Heat Capacity 460 J/kg·K0.11 BTU/lb·°F · Latent Heat of Fusion 250 J/g107 BTU/lb · Max Service Temperature (continuous) 200°C392 °F · Min Service Temperature -30°C-22 °F
Electrical
Conductivity and insulation.
Electrical Conductivity
Electrical Resistivity
Chemical & Environmental
Corrosion and environmental resistance (0–100 scores).
Galvanic Potential (seawater, vs SCE)
Corrosion Resistance
Manufacturability
FabDigit workshop ratings (0–100 scores) — how each material behaves on the machine.
Machinability
Machinability Rating (AISI 1212 = 100 %)
Weldability
Castability
Polishability
Same in both: Formability (cold) 20 / 100 · Brazeability / Solderability 35 / 100
Sustainability
Primary-production footprint per kilogram.
Embodied Energy (primary production)
Embodied Water
Typical Recycled Content
Same in both: Embodied Carbon (primary production) 2.6 kg CO₂/kg
Common Calculations
Ratios derived from the values above.
Specific Strength (UTS / density)
Specific Stiffness (E / density)
Modulus of Resilience
Thermal Diffusivity
Thermal Shock Resistance Index
Strength versus weight
Yield strength against density for every steel grade in the FabDigit library; the compared grades are highlighted. Up and left is stronger for its weight.
Manufacturing and finishing
| Capability | A3 | A8 |
|---|---|---|
| Default condition | — | Annealed |
| Relative cost | $$$ Premium | $$$ Premium |
| Min. machined wall | 0.8 mm | 0.8 mm |
| Best machined surface | Ra 1.6 µm | Ra 1.6 µm |
Both are offered for CNC machining. Both take the same 38 finishes: AlCrN, AlTiN, Black Oxide, CVD Al2O3, CVD TiCN, CVD TiN, Cerakote, Chrome Plating, Copper Plating, CrN, DLC, E-Coating and 26 more.
A3 vs A8 — frequently asked
Is A8 stronger than A3?
Yes. A8 has a typical yield strength of 500 MPa (72.5 ksi) against 430 MPa (62.4 ksi) for A3 — about 16% more. Tensile strength is 780 MPa (113 ksi) vs 760 MPa (110 ksi).
Which is cheaper, A3 or A8?
Both sit in the same relative cost tier ($$$, premium); the part price will be decided by machining time, tolerance and quantity rather than by the material.
Which is easier to machine, A3 or A8?
A8, by a small margin. Both rate fair for machinability — 45/100 against 38/100 for A3; for welding the order is A8 first (poor, 20/100) then A3 (poor, 15/100).
Ready to make it?
Upload a CAD file and FabDigit prices the part in A3 and A8 side by side — material, machining time, tolerance and finish in one quote. Certified material data ships with the order on request.
Typical handbook values for the conditions named above, normalised for comparison. Hardness on non-Brinell scales is converted approximately for charting only. Request certified data with your order for design-critical properties.